/*
* Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
* JZ4740 SoC RTC driver
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#define JZ_REG_RTC_CTRL 0x00
#define JZ_REG_RTC_SEC 0x04
#define JZ_REG_RTC_SEC_ALARM 0x08
#define JZ_REG_RTC_REGULATOR 0x0C
#define JZ_REG_RTC_HIBERNATE 0x20
#define JZ_REG_RTC_SCRATCHPAD 0x34
#define JZ_RTC_CTRL_WRDY BIT(7)
#define JZ_RTC_CTRL_1HZ BIT(6)
#define JZ_RTC_CTRL_1HZ_IRQ BIT(5)
#define JZ_RTC_CTRL_AF BIT(4)
#define JZ_RTC_CTRL_AF_IRQ BIT(3)
#define JZ_RTC_CTRL_AE BIT(2)
#define JZ_RTC_CTRL_ENABLE BIT(0)
struct jz4740_rtc {
struct resource *mem;
void __iomem *base;
struct rtc_device *rtc;
unsigned int irq;
spinlock_t lock;
};
static inline uint32_t jz4740_rtc_reg_read(struct jz4740_rtc *rtc, size_t reg)
{
return readl(rtc->base + reg);
}
static int jz4740_rtc_wait_write_ready(struct jz4740_rtc *rtc)
{
uint32_t ctrl;
int timeout = 1000;
do {
ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
} while (!(ctrl & JZ_RTC_CTRL_WRDY) && --timeout);
return timeout ? 0 : -EIO;
}
static inline int jz4740_rtc_reg_write(struct jz4740_rtc *rtc, size_t reg,
uint32_t val)
{
int ret;
ret = jz4740_rtc_wait_write_ready(rtc);
if (ret == 0)
writel(val, rtc->base + reg);
return ret;
}
static int jz4740_rtc_ctrl_set_bits(struct jz4740_rtc *rtc, uint32_t mask,
bool set)
{
int ret;
unsigned long flags;
uint32_t ctrl;
spin_lock_irqsave(&rtc->lock, flags);
ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
/* Don't clear interrupt flags by accident */
ctrl |= JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF;
if (set)
ctrl |= mask;
else
ctrl &= ~mask;
ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_CTRL, ctrl);
spin_unlock_irqrestore(&rtc->lock, flags);
return ret;
}
static int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
uint32_t secs, secs2;
int timeout = 5;
/* If the seconds register is read while it is updated, it can contain a
* bogus value. This can be avoided by making sure that two consecutive
* reads have the same value.
*/
secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
while (secs != secs2 && --timeout) {
secs = secs2;
secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
}
if (timeout == 0)
return -EIO;
rtc_time_to_tm(secs, time);
return rtc_valid_tm(time);
}
static int jz4740_rtc_set_mmss(struct device *dev, unsigned long secs)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, secs);
}
static int jz4740_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
uint32_t secs;
uint32_t ctrl;
secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC_ALARM);
ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
alrm->enabled = !!(ctrl & JZ_RTC_CTRL_AE);
alrm->pending = !!(ctrl & JZ_RTC_CTRL_AF);
rtc_time_to_tm(secs, &alrm->time);
return rtc_valid_tm(&alrm->time);
}
static int jz4740_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
int ret;
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
unsigned long secs;
rtc_tm_to_time(&alrm->time, &secs);
ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC_ALARM, secs);
if (!ret)
ret = jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AE, alrm->enabled);
return ret;
}
static int jz4740_rtc_update_irq_enable(struct device *dev, unsigned int enable)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
return jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_1HZ_IRQ, enable);
}
static int jz4740_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
return jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AF_IRQ, enable);
}
static struct rtc_class_ops jz4740_rtc_ops = {
.read_time = jz4740_rtc_read_time,
.set_mmss = jz4740_rtc_set_mmss,
.read_alarm = jz4740_rtc_read_alarm,
.set_alarm = jz4740_rtc_set_alarm,
.update_irq_enable = jz4740_rtc_update_irq_enable,
.alarm_irq_enable = jz4740_rtc_alarm_irq_enable,
};
static irqreturn_t jz4740_rtc_irq(int irq, void *data)
{
struct jz4740_rtc *rtc = data;
uint32_t ctrl;
unsigned long events = 0;
ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
if (ctrl & JZ_RTC_CTRL_1HZ)
events |= (RTC_UF | RTC_IRQF);
if (ctrl & JZ_RTC_CTRL_AF)
events |= (RTC_AF | RTC_IRQF);
rtc_update_irq(rtc->rtc, 1, events);
jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF, false);
return IRQ_HANDLED;
}
void jz4740_rtc_poweroff(struct device *dev)
{
struct jz4740_rtc *rtc = dev_get_drvdata(dev);
jz4740_rtc_reg_write(rtc, JZ_REG_RTC_HIBERNATE, 1);
}
EXPORT_SYMBOL_GPL(jz4740_rtc_poweroff);
static int __devinit jz4740_rtc_probe(struct platform_device *pdev)
{
int ret;
struct jz4740_rtc *rtc;
uint32_t scratchpad;
rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
if (!rtc)
return -ENOMEM;
rtc->irq = platform_get_irq(pdev, 0);
if (rtc->irq < 0) {
ret = -ENOENT;
dev_err(&pdev->dev, "Failed to get platform irq\n");
goto err_free;
}
rtc->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!rtc->mem) {
ret = -ENOENT;
dev_err(&pdev->dev, "Failed to get platform mmio memory\n");
goto err_free;
}
rtc->mem = request_mem_region(rtc->mem->start, resource_size(rtc->mem),
pdev->name);
if (!rtc->mem) {
ret = -EBUSY;
dev_err(&pdev->dev, "Failed to request mmio memory region\n");
goto err_free;
}
rtc->base = ioremap_nocache(rtc->mem->start, resource_size(rtc->mem));
if (!rtc->base) {
ret = -EBUSY;
dev_err(&pdev->dev, "Failed to ioremap mmio memory\n");
goto err_release_mem_region;
}
spin_lock_init(&rtc->lock);
platform_set_drvdata(pdev, rtc);
rtc->rtc = rtc_device_register(pdev->name, &pdev->dev, &jz4740_rtc_ops,
THIS_MODULE);
if (IS_ERR(rtc->rtc)) {
ret = PTR_ERR(rtc->rtc);
dev_err(&pdev->dev, "Failed to register rtc device: %d\n", ret);
goto err_iounmap;
}
ret = request_irq(rtc->irq, jz4740_rtc_irq, 0,
pdev->name, rtc);
if (ret) {
dev_err(&pdev->dev, "Failed to request rtc irq: %d\n", ret);
goto err_unregister_rtc;
}
scratchpad = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD);
if (scratchpad != 0x12345678) {
ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678);
ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, 0);
if (ret) {
dev_err(&pdev->dev, "Could not write write to RTC registers\n");
goto err_free_irq;
}
}
return 0;
err_free_irq:
free_irq(rtc->irq, rtc);
err_unregister_rtc:
rtc_device_unregister(rtc->rtc);
err_iounmap:
platform_set_drvdata(pdev, NULL);
iounmap(rtc->base);
err_release_mem_region:
release_mem_region(rtc->mem->start, resource_size(rtc->mem));
err_free:
kfree(rtc);
return ret;
}
static int __devexit jz4740_rtc_remove(struct platform_device *pdev)
{
struct jz4740_rtc *rtc = platform_get_drvdata(pdev);
free_irq(rtc->irq, rtc);
rtc_device_unregister(rtc->rtc);
iounmap(rtc->base);
release_mem_region(rtc->mem->start, resource_size(rtc->mem));
kfree(rtc);
platform_set_drvdata(pdev, NULL);
return 0;
}
struct platform_driver jz4740_rtc_driver = {
.probe = jz4740_rtc_probe,
.remove = __devexit_p(jz4740_rtc_remove),
.driver = {
.name = "jz4740-rtc",
.owner = THIS_MODULE,
},
};
static int __init jz4740_rtc_init(void)
{
return platform_driver_register(&jz4740_rtc_driver);
}
module_init(jz4740_rtc_init);
static void __exit jz4740_rtc_exit(void)
{
platform_driver_unregister(&jz4740_rtc_driver);
}
module_exit(jz4740_rtc_exit);
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("RTC driver for the JZ4740 SoC\n");
MODULE_ALIAS("platform:jz4740-rtc");
